Select "Linker -> General" in the left pane, and change the Output File
to a file with a ".p" extension.

Next, select "Linker -> Input" and set "Additional Dependencies"
to "ac3d.lib". If you did not perform the Setting
up the compiler step, either do so after you apply this change, or include the
library path in your compiler options.

The only remaining step is when you have finished creating your plugin. At that point,
make sure to set your Build configuration from Debug to Release.